Fin-tube heat exchanger

ABSTRACT

A heat exchanger includes: fins formed in a wavy shape; and a tube attached with the wavy fins and bent in a zigzag shape. A contact area between the tube and the fins are maximized to thus considerably enhance heat transfer through the fins.

RELATED APPLICATION

The present disclosure relates to subject matter contained in priority Korean Application No. 10-2006-0001085, filed on Jan. 4, 2006, which is herein incorporated by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates generally to a fin-tube heat exchanger, and, more particularly, to a fin-tube heat exchanger applied for a direct cooling type refrigerator capable of enhancing the efficiency of heat exchange with ambient air.

2. Description of the Related Art

FIG. 1 illustrates a general shape of a cabinet 1 of a refrigerator having a refrigerating chamber 10 and a freezing chamber 20. In general, in a direct cooling type refrigerator, an evaporator is tightly attached in the refrigerating chamber 10 or the freezing chamber 20, or a mounting plate is formed as an evaporator to directly cool the refrigerating chamber 10 or the freezing chamber 20. Recently, an indirect cooling type refrigerator in which cooling air is injected to the refrigerating chamber 10 and the freezing chamber 20 has been commonly used. Compared with the indirect cooling type refrigerator, the direct cooling type refrigerator is operated based on a principle that cooling air of the evaporator is directly supplied to the refrigerating chamber 10 or freezing chamber 20 according to natural convection phenomenon of cooled air around the evaporator, instead of separately generating a large quantity of cooling air.

FIG. 2 illustrates a side view of the structure of the direct cooling type refrigerator of FIG. 1. FIG. 3 illustrates a schematic block diagram showing the construction of a refrigerating cycle of the direct cooling type refrigerator of FIG. 2. As shown in FIGS. 2 and 3, the direct cooling type refrigerator 9 has a refrigerating cycle in which two evaporators 50 and 60 are connected in series. Namely, the direct cooling type refrigerator 9 includes a cabinet 1 having a refrigerating chamber 10 and a freezing chamber 20, a compressor 30 for compressing the refrigerant of the refrigerating cycle and generally formed at a lower portion of the cabinet 1, a condenser 40 for receiving compressed refrigerant in a direction of reference numeral 88 along a refrigerant passage 99 and condensing the refrigerant while emanating heat, a first evaporator 50 tightly attached on a rear surface of the refrigerating chamber 10 and cooling the refrigerating chamber 10 by evaporating the refrigerant from the condenser 40, a second evaporator 60 tightly attached on a rear surface of the freezing chamber 20 in order to evaporate the refrigerant either from the first evaporator 50 or from the condenser 40 to thus cool the freezing chamber 20, and a valve 80 for selectively opening a first tube 81 that connects the condenser 40 and the first evaporator 50 and a second tube 82 that connects the condenser 40 and the second evaporator 60.

The condenser 40 operates as a heat exchanger to exchange heat generated as the refrigerant is condensed with ambient air. The evaporators 50 and 60 also need to effectively absorb ambient heat as the refrigerant is evaporated.

FIG. 4 illustrates a perspective view of the structure of a conventional heat exchanger of a direct cooling type refrigerator. FIG. 5 illustrates a side view of the heat exchanger of FIG. 4. In the heat exchanger as shown in FIGS. 4 and 5, a plurality of fins 42 for helping heat exchange around the tube 41 through which the refrigerant flows are attached around the tube 41. The plurality of fins 42 are braze-welded in a state that they point-contact with the tube 41, as represented by reference numeral 42 a. Heat exchange between the tube 41 and the fins 42 occurs at this contact.

SUMMARY

In one general aspect, a heat exchanger capable of improving performance of exchanging heat with ambient air and a method of manufacturing such a heat exchanger are provided. Implementations of the heat exchanger may improve freezing and noise prevention performance of a direct cooling type refrigerator by applying the heat exchanger to a condenser or an evaporator of the direct cooling type refrigerator.

To this end, a heat exchanger may include a tube through which a refrigerant flows, and a fin attached to the tube. The fin may have a nonlinear shape at an interface between the fin and the tube. More particularly, the fin may be shaped to conform with a shape of the tube at the interface between the fin and the tube. The interface between the fin and the tube may define an arc and the fin may have an arcuate shape at the interface. Also, the fin or the tube may have a serpentine shape.

The tube of the heat exchanger may include multiple parallel portions and the fin may interface with at least two of the parallel portions of the tube and may be shaped to conform with a shape of the tube at the interfaces between the fin and the at least two parallel portions.

In another general aspect, a heat exchanger may include a tube through which a refrigerant flows, and a plurality of fins attached to the tube. Each of the fins may have a nonlinear shape at an interface between the fin and the tube. More particularly, each of the fins may be shaped to conform with a shape of the tube at the interface between the fin and the tube. Specifically, the interface between the fin and the tube may define an arc, and the fin may have an arcuate shape at the interface.

The tube of the heat exchanger may include multiple parallel portions and each of the fins may interface with at least two of the parallel portions of the tube and may be shaped to conform with a shape of the tube at the interfaces between each of the fins and the at least two parallel portions.

Also, a first group of the fins may be attached to an upper surface of the tube and a second group of the fins may be attached to a lower surface of the tube. The fins may be arranged in such a manner that each fin of the first group is placed between two adjacent fins of the second group.

In yet another general aspect, a refrigerator using heat exchangers as explained above is provided.

In another general aspect, a method of manufacturing a heat exchanger includes providing a tube through which a refrigerant flows, and attaching a plurality of fins to the tube. Each fin may have a nonlinear shape at an interface between the fin and the tube. More particularly, each fin may be shaped to conform with a shape of the tube at the interface between the fin and the tube. Attaching the fins to the tube may include attaching a first group of fins to an upper surface of the tube and attaching a second group of fins to a lower surface of the tube. Each fin of the first group may be placed between two adjacent fins of the second group.

In another general aspect, a heat exchanger may include fins formed in a wavy shape, and a tube attached with the wavy fins and bent in a zigzag shape.

Because the fins for assisting heat exchanging between ambient air and a fluid passing through the tube are formed in the wavy shape and the tube is attached with the wavy surface of the fins and line-contacts or surface-contacts, not point-contacts, the heat transfer area between the fins and tube is increased and the performance of heat exchanging between the tube and the ambient air is highly improved.

The wavy surfaces of the fins are respectively attached to the upper surface and the lower surface of the tube, so heat of a fluid in the tube can be heat-exchanged with the ambient air through the wavy fins. In this case, the fins attached to the upper surface of the tube and the fins attached to the lower surface of the tube are not positioned on the same planes (namely, they are positioned on different planes), whereby the ambient air of the heat exchanger can be heat-exchanged with fin having a larger sectional area.

For example, when the heat exchanger works as the condenser so a hot refrigerant flows in the tube and the ambient air has a low temperature compared with that of the heat exchanger, because the fins are arranged in the crisscross manner on different planes of the tube, each fin can contact with cold air which has not been heated by adjacent fins. Namely, when the heat exchanger is positioned horizontally and there is no flow in the ambient air, air heated after being heat exchanged with the fins is naturally move upward by convection without being heat exchanged with the adjacent fins. Accordingly, the fins arranged in the crisscross manner can contact with the ambient cold air and maximize the cooling efficiency.

The fins surface-attached to the upper surface of the tube and the fins surface-attached to the lower surface of the tube are arranged at uniform gap therebetween, so its mass-production can be improved in terms of fabrication.

An inner curvature of the wavy fins may be the same as an outer diameter of a section of the tube. Accordingly, because the fins are formed in a wrapping or covering manner, a larger contact area between the tube and the fins can be obtained.

In addition, both ends of the fins may be attached to the tube in the wrapping manner. Thus, the heat transfer efficiency between the both ends of the tube and fins can be improved and the bonding strength between the fins the tube can be improved.

Implementations may provide a direct cooling type refrigerator in which the heat exchanger is applied for the condenser and the evaporator.

Other features will be apparent from the following description, including the accompanying drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a general shape of a cabinet of a refrigerator;

FIG. 2 is a side view showing the structure of the direct cooling type refrigerator of FIG. 1;

FIG. 3 is a schematic block diagram showing a refrigerating cycle of the direct cooling type refrigerator of FIG. 2;

FIG. 4 is a perspective view showing the structure of a conventional heat exchanger of the direct cooling type refrigerator of FIG. 1;

FIG. 5 is a side view of the conventional heat exchanger of FIG. 4; and

FIGS. 6 to 8 are views showing the structure of a heat exchanger, in which FIG. 6 is a perspective view showing the structure of the heat exchanger, FIG. 7 is a sectional view taken along line VII-VII of FIG. 6, and FIG. 8 is a front view of the heat exchanger of FIG. 6.

DETAILED DESCRIPTION

FIGS. 6 to 8 illustrate the structure of a heat exchanger. As shown in FIGS. 6 to 8, a heat exchanger 100 includes a tube 101 that allows a fluid to flow therein, and fins 102 and 103 having a nonlinear shape at an interface between the fins 102 and 103 and the tube 101. For example, as shown in FIG. 6, the fins 102 and 103 may be formed in a wavy shape and attached to the top and bottom portions 102 a and 103 a of the tube 101.

In general, the fins may be shaped to conform with a shape of the tube at the interface between the fins and the tube. For example, a curvature of the inner surface of the wavy fins 102 and 103 may be substantially the same as the outer diameter of the cross-section of the tube 101, so the contact areas 102 a and 103 a can be maximized.

As shown in FIG. 8, the upper fins 102 attached to the upper portion of the tube 101 and the lower fins 103 attached to the lower portion of the tube 101 are arranged in an interdigital manner on different planes with a certain interval therebetween. Thus, each upper fin is placed between two adjacent lower fins. This arrangement also improves the heat exchange capability of the heat exchanger, particularly when the heat exchanger 100 is placed horizontally, since the interdigital arrangement of fins 102 and 103 of the heat exchanger 100 can increase the chances of heat exchanging with ambient cold air.

Also, because both ends 102 b and 103 b of the fins 102 and 103 are attached to the tube 101 in a wrapping manner, the heat transfer between the fins 102 and 103 and the tube 101 can be further increased and the bonding strength between the fins 102 and 103 and the tube 101 can be also increased.

The heat exchanger 100 constructed as described above can be utilized for various purposes. For example, it can be advantageously applied for the condenser of a direct cooling type refrigerator, for the following reasons. Because the cooling mechanism of a direct cooling type refrigerator is buried in an insulation panel of the cabinet of the refrigerator, a blow fan is not provided. So, if the heat exchange with the ambient air of the condenser is not sufficient, a refrigerant pipe with a sufficient length should be obtained to release the heat generated from the condenser 40. If the tube of the condenser 40 is lengthened, the amount of refrigerant to be filled in the refrigerant pipe of the condenser 40 is unnecessarily increased, and, when the operation of the compressor is stopped, the amount of high temperature refrigerant flowing into the evaporator due to an internal pressure difference increases, which increase the noise at an outlet of the evaporator. In addition, when the compressor is driven, time to increase the pressure of the condenser 40 to a level required for condensing is lengthened, degrading the efficiency of the refrigerating cycle.

Thus, by applying the heat exchanger 100 to the condenser 30 of the direct cooling type refrigerator, the length of the pipe of the condenser can be reduced as the heat release efficiency is improved. As a result, the filling amount of the refrigerant required for the refrigerating cycle can be reduced, which reduces the noise generated from the high temperature refrigerant flowing to the evaporator while the compressor is not working, and also reduces the time to reach the condensing pressure required for the condensing operation of the condenser. Therefore, a quiet and quick operation can be implemented.

In addition, the heat exchanger also can be applied to the evaporator to improve the efficiency of heat transfer of the evaporator, thereby effectively refrigerating the refrigerating chamber or the freezing chamber.

Implementations of the fin-tube heat exchanger may offer a number of advantages.

For example, with the wavy fins and the tube attached to the wavy surface of the fins and bent in a zigzag shape, the contact area between the tube and the fins can be maximized in order to increase the heat transfer area between the fins and the tube. Thus, compared to the conventional structure, the efficiency of heat transfer may be improved.

Also, as noted, the wavy surface of the wavy fins may be attached to the upper and lower surfaces of the tube with the fins surface-attached to the upper surface of the tube and the fins surface-attached to the lower surface of the tube and arranged in an interdigital manner on different planes of the tube. Accordingly, the degradation of heat transfer performance by adjacent fins can be minimized.

Moreover, because both ends of the fins are attached to the tube in a wrapping manner, the performance of heat transfer between the tube and the fins can be enhanced and the bonding strength between the fins and the tube can be also improved.

Additionally, by applying the heat exchanger with the improved heat exchange efficiency to the condenser or the evaporator of a direct cooling type refrigerator, the length of the pipe of the condenser or the evaporator can be reduced as the heat release efficiency is improved. Thus, the filling amount of refrigerant required for the refrigerating cycle can be reduced, and an amount of noise generated from the high temperature refrigerant flowing into the evaporator while the compressor is stopped in operation can also be reduced. Also time to reach the condensing pressure required for the condensing operation can be reduced. Thus, quiet and quick operation of the refrigerator can be implemented.

Other implementations are within the scope of the following claims. 

1. A heat exchanger comprising: a tube through which a refrigerant flows; and a fin attached to the tube, the fin having a nonlinear shape at an interface between the fin and the tube.
 2. The heat exchanger of claim 1, wherein the fin is shaped to conform with a shape of the tube at the interface between the fin and the tube.
 3. The heat exchanger of claim 2, wherein the interface between the fin and the tube defines an arc and the fin has an arcuate shape at the interface.
 4. The heat exchanger of claim 3, wherein the fin has a serpentine shape.
 5. The heat exchanger of claim 1, wherein the tube has a serpentine shape.
 6. The heat exchanger of claim 5, wherein the tube includes multiple parallel portions.
 7. The heat exchanger of claim 6, wherein the fin interfaces with at least two of the parallel portions of the tube and is shaped to conform with a shape of the tube at the interfaces between the fin and the at least two parallel portions.
 8. The heat exchanger of claim 7, wherein the interfaces between the fin and the at least two parallel portions of the tube define arcs and the fin has arcuate shapes at the interfaces.
 9. The heat exchanger of claim 8, wherein the fin has a serpentine shape.
 10. A heat exchanger comprising: a tube through which a refrigerant flows; and a plurality of fins attached to the tube, each of the fins having a nonlinear shape at an interface between the fin and the tube.
 11. The heat exchanger of claim 10, wherein each of the fins is shaped to conform with a shape of the tube at the interface between the fin and the tube.
 12. The heat exchanger of claim 11, wherein the interface between each of the fins and the tube defines an arc and each of the fins has an arcuate shape at the interface.
 13. The heat exchanger of claim 12, wherein each of the fins has a serpentine shape.
 14. The heat exchanger of claim 10, wherein the tube has a serpentine shape.
 15. The heat exchanger of claim 14, wherein the tube includes multiple parallel portions.
 16. The heat exchanger of claim 15, wherein each of the fins interfaces with at least two of the parallel portions of the tube and is shaped to conform with a shape of the tube at the interfaces between the the fin and the at least two parallel portions.
 17. The heat exchanger of claim 16, wherein the interfaces between each of the fins and the at least two parallel portions of the tube define arcs and each of the fins has arcuate shapes at the interfaces.
 18. The heat exchanger of claim 17, wherein each of the fins has a serpentine shape.
 19. The heat exchanger of claim 10, wherein a first group of the fins are attached to an upper surface of the tube and a second group of the fins are attached to a lower surface of the tube.
 20. The heat exchanger of claim 19, wherein each fin of the first group of fins is placed between two adjacent fins of the second group of fins.
 21. A heat exchanger comprising: a tube through which a refrigerant flows; a first group of fins attached to an upper surface of the tube; and a second group of fins attached to a lower surface of the tube, wherein each fin of the first group of fins is placed between two adjacent fins of the second group of fins.
 22. A refrigerator comprising the heat exchanger of claim
 1. 23. A method of manufacturing a heat exchanger, comprising: providing a tube through which a refrigerant flows; and attaching a plurality of fins to the tube, each of the fins having a nonlinear shape at an interface between the fin and the tube.
 24. The method of claim 23, wherein each of the fins is shaped to conform with a shape of the tube at the interface between the fin and the tube.
 25. The method of claim 23, wherein attaching the fins to the tube comprises attaching a first group of the fins to an upper surface of the tube and attaching a second group of the fins to a lower surface of the tube.
 26. The method of claim 25, wherein each fin of the first group of fins is placed between two adjacent fins of the second group of fins. 